Spray gun for paints and the like



Feb. 28, 1939. A KRA TZBERGER 2,149,181

SPRAY GUN-FOR PAINTS-AND THE LIKE 2 Sheets-Sheet 1' Filed Feb. 18,1956 1. \L... A fxnvui i 0. 1 1

A. KRAUTZBERGER SPRAY GUN FOR PAINTS AND THE LIKE Fe l). 28, 193-9.

2 Sheets-Sheet 2 Filed Feb. 18, 1956 v Patented Feb. 28, 1939 UNITEDswag,

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rA'rENr ca ries SPRAY GUN FOB PAINTS THE Albert Krautzberger, Leipzig,Germany Application February 18,1936, Serial No. 64,5s4

In Germany February. 21, 1935 3 Claims.

In spray guns used for paint, varnish, enamel and the like the liquid orsemi-liquid substance dealt with, which I'shall hereinaftergenerallyterioration oi the work. l e

To prevent this I arrange the valve controlling mechanism in a closedchamber in the gun,'and provide for admission of compressed airto thatchamber, so that this air prevents entrance of 20 point through thepassages in which the valve rods work.

Two examples of apparatus according to the invention are shown intheaccompanyingdraw- 25 Fig. 1 is a side view, partly in section andpartly broken away, showing one form of construction,

Fig. 2 is a fragmentary transverse vertical sectionofFig. 1, 1

Fig. 3 is a side view of the second form of con- 30 struction, V d IFig. 3a is a fragmentary, transverse vertical section of a detailthereof, I

Fig. 4 is a longitudinal vertical section of the form of invention ofFig. 3, and 35 Fig. 5 is a fragmentary sectional view showing amodification of a detail. I

Referring first to the construction shown in Figs. 1 and 2 of thedrawings, there is a roughly cylindrical chamber b in the body ll of thegun,

40 closed at the sides by removable covers d. in which there arebearings for a spindle p. The ends of the spindle project from thecovers d, so that they engage the-limbs of a forked trigger q foractuating the spindle. The limbs are springy,

45 so that they can be disengaged from the spindle 11. and on removal ofthe covers the mechanism in the chamber can be taken out for cleaning,repair or renewal. Within the chamber b the spindle 9 has fixed theretotwo fingers 9. The finger a 60 is forked to straddle the valve rodbetween collar members II and I! fixed to the rod and thus movement ofthe finger a actuates a hollow valve rod 1:, and the finger g actuates adouble armed lever 11 pivoted at i. To the lever n is connected 0.

'55 plunger 0 abutting against the stem 71. of the supply becomesinaccurate, with consequent de-- main air valve h, which is normallyclosed by a spring I but which can be opened by pulling the trigger qand thus causing the finger g to rotate the lever n and depress theplunger. It is obvious that movement of thestem h by the spring willrock the lever 12. which, in turn, will rock the fingers g and o andthus move the rod is to the left (Fig. 1) to valve closing position.'-The hollow rod is terminates in the usual frusto-conical valve portion13 which fits in the usual nozzle w. The W nozzle is supplied with paintthorugh a pipe 12 which'communicates with the nozzle through a passage Hcontrolled by a valve v. The plunger rod 0 abuts at the top against ascrew r, which can be adjusted so that the spring I cannot fully 15close the valve h. In that case there is a constant flow of air throughthe gun when it is not in operation, to keep the passages clear and tokeep it warm, if the air is heated. Adjustment of the screw 1 can alsobe made for the purpose of causing the air valve h to be opened beforethe paint valve is opened, instead of opening the two valvessimultaneously, as may sometimes be desired. The air valve h can-beopened before the paint valve I3 is opened by loosening the screw 1'slight- -ly. This raises plungero, depresses the nose of the lever nwhich in turn depresses the finger g and swings the finger a to the left(Fig. 1). This action forces the finger g against the left hand abutmenton the rod k and provides play for the finger a when the trigger ispulled while at the same time not providing play as far as the openingof the air valve h is concerned. Thus, with the parts arranged as above,the air valve-h will' be opened slightlybei'ore the finger g engages theright hand abutment on the rod 70 and moves the latter to open the valve'13.

when the valve h is open compressed air flows through a conduit 2 to thesprayer nozzle. From this conduit a small duct I leads to the chamber 40b, admitting compressed air to that chamber for the purpose ofpreventing entrance of paint, fumes or'dirt. Avalve in the duct 3enables the air flow to the chamber b to be controlled. There may beanother duct in part of the air valve. For instance, the stem of thevalve It may be hollow and provided with an inlet opening 5 adjacent thehead of the valve. Openings 5' may be provided in said stern adjacentthe top thereof to permit the flow of air through the openings 0' formedin the head of the plunger 0. This modified structure is seen in Fig. 5.

Above the chamber 17 there is an oil cup m with lubricating ductsleading to suitable parts of the chamber. The compressed air in thechamber in 55.

a constant state 01' agitation, ensures that the oil is carried to allthe parts requiring lubrication.

The rod k, controlling the paint-valve w, is made hollow for the purposeof conducting a stream of air to the central orifice of the nozzle.Paint is fed to the valve w through a valve 12 and a conduit 1) leadingto a suitable source of supply (not shown). Within the chamber b the rodhas a hole for admitting this air from the chamber to the bore in therod.

The apparatus shown in Figs. 3, 3a. and 4 is intended mainly fordecorative work. The gun in this case also has a chamber b closed at thesides by circular covers 01 with a spindle 11 mounted centrally therein,but the spindle is rotated by means of a yoke q (Fig. 30-) having afinger rest on top of the gun. Paint is supplied to a valve 112 througha valve 12 and conduit 0' as in the ilrst described form of theinvention.

The spindle has a finger g for opening the spring loaded air valve 71.,and a crank t for opening the paint valve is. The crank for this purposeactuates a rod u fixed to a spring loaded bracket s, to which the valveis is fixed.

If the paint is supplied under pressure there is risk that particlesthereof may penetrate into the chamber b through the bearings of thevalve mechanism. To prevent this I arrange, at the inlet into thechamber out of which the nozzle opens, a pressure reducing valve orequivalent device, reducing the pressure in that chamber to the moderatevalue required for emitting the paint. The presence of the valve 3 isimportant for the reason that it is meant to prevent the formation oftoo great a pressure in chamber b, since spraying is often done underpressure of 3 atm'ospheres or more and danger exists that the largecovers (I will not be able to resist the pressure and will be blown off,which will endanger the laborer and which is likely to injure himseverely.

It is important also that the foul air be led from the chamber b to ,therod is, which makes it also available to help the diffusion of thespraying material, thereby making use of the excess pressure from thechamber b.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is: 1. In a spray gun for-paint or the like, thecombination 01' a nozzle, a valve controlling the emission of paint orthe like from said nozzle, said valve including an elongated hollowstem, an air conduit leading to said nozzle, a valve controlling theadmission of compressed air to said air conduit, a chamber in said gun,a portion of said hollow stem extending into said chamber and having anopening through a wall thereof, means in said chamber for normallyactuating both of said valves simultaneously, one wall of said chamberbeing formed to provide a passage to said air conduit, and valve meansin said passage for regulating the amount of compressed air admitted tosaid chamber through said passage.

2. In a spray gun for paint or the like, the combination of a nozzle, avalve controlling the emission of paint or the like from said nozzle,said valve including an elongated hollow stem, an air conduit leading tosaid nozzle, a valve controlling the admission of compressed air to saidair conduit, a chamber in said gun, a portion 01' said hollow stemextending into said chamber and having an opening through a wallthereof, means in said chamber for normally actuating both of saidvalves simultaneously, one wall of said chamber being formed to providea passage to said air conduit, valve means in said passage forregulating the amount of compressed air admitted to said chamber throughsaid passage, and means associated with said valve actuat ng means andselectively operable to cause said valves to be actuated successively.

3. In a spray gun for paint or the like, the u combination of a nozzle,a valve controlling the emission of paint or the like from said nozzle,said valve including an elongated hollow stem, an air conduit leading tosaid nozzle, a valve controlling the admission oi compressed air to saidair conduit, a chamber in said gun, a portion of said hollow stemextending into said chamber and having an opening through awall-thereof, means in said chamber for normally actuating both 01 saidvalves simultaneously, one wall of said chamber being formed to providea passage to said air conduit, valve means in said passage forregulating the amount of compressed air admitted to said chamber throughsaid passage, and means associated with said valve actuating means andselectively operable to cause said valves to be actuated successively,said last named means also being selectively operable to prevent thecomplete closing 01' said air valve.

ALBERT mum'rznnnana.

